11-15 February 2013
Vienna University of Technology
Europe/Vienna timezone

A Time Projection Chamber for High-Rate Experiments: Towards an Upgrade of the ALICE TPC

11 Feb 2013, 15:15
EI7 (Vienna University of Technology)


Vienna University of Technology

Talk Plenary 2


Bernhard Ketzer (Technische Universitaet Muenchen (DE))


A Time Projection Chamber (TPC) is a powerful detector for 3-dimensional tracking and particle identification for ultra-high multiplicity events. It is the central tracking device of many experiments, e.g. the ALICE experiment at CERN. The necessity of a switching electrostatic gate, which prevents ions produced in the amplification region of MWPCs from entering the drift volume, however, restricts its application to trigger rates of the order of 1 kHz. Charge amplification by Gas Electron Multiplier (GEM) foils instead of proportional wires oers an intrinsic suppression of the ion backflow, although not to the same level as a gating grid. Detailed Monte Carlo simulations have shown that the distortions due to residual space charge from back-drifting ions can be limited to a few cm, and thus can be corrected using standard calibration techniques. A prototype GEM-TPC has been built which is the detector with the largest active volume of this kind up to now. It has been commissioned with cosmics and particle beams at the FOPI experiment at GSI, and was employed for a physics measurement with pion beams. For future operation of the ALICE TPC at the CERN LHC beyond 2019, where Pb-Pb collision rates of 50 kHz are expected, it is planned to replace the existing MWPCs by GEM detectors, operated in a continuous, triggerless readout mode, thus allowing an increase in event rate by a factor of 100. As a first step of the R&D program, a prototype of an Inner Readout Chamber was equipped with large-size GEM foils and exposed to beams of protons, pions and electrons from the CERN PS. In this presentation, new results will be shown concerning ion backflow, spatial and momentum resolution of a GEM-TPC in a running experiment, detector calibration, dE=dx resolution, and high-rate performance with both detector prototypes. The perspectives of a GEM-TPC for ALICE with continuous readout will be discussed and the expected performance will be presented.
quote your primary experiment ALICE

Primary author

Bernhard Ketzer (Technische Universitaet Muenchen (DE))


Bernd Voss (Helmholtzzentrum für Schwerionenforschung GmbH (GSI)) Christian Hoeppner (Technische Universitaet Muenchen (DE)) Dr Christian Joachim Schmidt (GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE)) Daniel Soyk (GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE)) Felix Valentin Boehmer (Technische Universitaet Muenchen (DE)) Dr Francesco Cusanno (Istituto Nazionale di Fisica Nucleare) Igor Konorov (Technische Universitaet Muenchen (DE)) Joerg Lothar Hehner (GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE)) Johann Zmeskal (A) Johannes Rauch (Technische Universität München) Klaus Peters (Institut fuer Experimentalphysik I) Dr Lars Schmitt (GSI Darmstadt) Markus Ball (Technische Universität München) Martin Emanuel Berger (Technische Universitaet Muenchen (DE)) Maxence Vandenbroucke (IRFU-CEA - Centre d'Etudes de Saclay (CEA)) Paul Buehler (SMI) Rahul Arora (GSI) Roman Schmitz (Helmholz-Inst. f. Strahl.- u. Kernp-Physikalisches Institut-Uni) Mr Sebastian Neubert (Technical University Munich) Sebastian Uhl (Technische Universitaet Muenchen (DE)) Stephan Paul (Institut fuer Theoretische Physik) Sverre Dorheim (Technische Universitaet Muenchen (DE)) Yvonne Leifels (G) laura fabbietti (Technische Universität München)

Presentation Materials